Lake Goodwin
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake Goodwin clear sky chart from 2005-11-06 to 2024-11-01.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	19% 9% 3 7% 5% 4 4 3 5% 6% 35%	101737
	Night	23% 11% 3 7% 5% 4 4 3 4 5% 31%	97276
Transparency	Day	49% 10% 14% 17% 8% 1	101492
	Night	54% 9% 13% 15% 7% 1	97167
Seeing	Day	24% 10% 19% 25% 17% 6%	15154
	Night	30% 8% 12% 25% 20% 4	23459

By Month

Percentage Cloud Cover NW (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	35% 18% 4 8% 5% 4 4 3 4 4 11%	2219
	11th to 20th	Day	24% 12% 4 8% 6% 4 5% 4 5% 6% 23%	2427
	21st to end	Day	33% 15% 4 10% 6% 6% 5% 3 4 5% 9%	2835
February	1st to 10th	Day	31% 13% 4 10% 5% 4 4 4 4 6% 16%	1710
	11th to 20th	Day	27% 14% 4 10% 5% 4 4 3 5% 5% 20%	1665
	21st to end	Day	27% 15% 3 9% 5% 3 4 4 6% 5% 19%	1470
March	1st to 10th	Day	18% 14% 4 9% 6% 6% 6% 4 6% 7% 21%	3200
	11th to 20th	Day	20% 9% 3 6% 5% 4 4 3 5% 6% 34%	3490
	21st to end	Day	25% 12% 4 10% 5% 5% 6% 4 5% 5% 18%	3963
April	1st to 10th	Day	23% 14% 3 8% 6% 5% 4 4 6% 6% 19%	2280
	11th to 20th	Day	21% 12% 3 8% 7% 5% 5% 3 5% 6% 25%	2286
	21st to end	Day	21% 12% 4 8% 6% 5% 5% 3 6% 6% 25%	2527
May	1st to 10th	Day	19% 8% 2 6% 4 4 3 3 5% 6% 39%	4420
	11th to 20th	Day	15% 6% 3 6% 4 4 5% 4 6% 9% 39%	4377
	21st to end	Day	28% 9% 3 8% 5% 4 4 3 5% 6% 25%	4813
June	1st to 10th	Day	21% 8% 3 7% 5% 4 5% 4 5% 7% 31%	2758
	11th to 20th	Day	20% 10% 3 8% 5% 5% 5% 4 6% 7% 28%	2850
	21st to end	Day	12% 7% 3 7% 5% 4 4 4 6% 7% 41%	2850
July	1st to 10th	Day	6% 4 2 4 3 2 2 2 3 4 67%	4740
	11th to 20th	Day	5% 3 1 3 3 2 2 3 3 5% 69%	4613
	21st to end	Day	12% 4 2 4 3 3 3 2 4 5% 58%	4790
August	1st to 10th	Day	5% 3 1 3 2 3 3 3 4 8% 64%	4354
	11th to 20th	Day	11% 6% 2 7% 4 4 5% 4 5% 8% 44%	4026
	21st to end	Day	14% 8% 3 7% 5% 4 3 3 3 6% 43%	4345
September	1st to 10th	Day	10% 7% 3 5% 4 4 4 2 5% 7% 50%	2280
	11th to 20th	Day	14% 8% 3 8% 4 4 5% 4 5% 6% 40%	2280
	21st to end	Day	18% 7% 3 7% 5% 4 3 4 6% 6% 37%	2008
October	1st to 10th	Day	20% 8% 3 9% 5% 4 4 5% 6% 7% 30%	1900
	11th to 20th	Day	25% 11% 3 8% 5% 4 4 3 6% 7% 24%	1900
	21st to end	Day	29% 10% 4 8% 5% 4 4 4 5% 6% 22%	1964
November	1st to 10th	Day	34% 10% 4 7% 5% 4 5% 4 5% 6% 17%	1516
	11th to 20th	Day	33% 10% 4 7% 4 4 4 3 4 5% 21%	1520
	21st to end	Day	33% 12% 4 6% 5% 3 5% 3 5% 7% 17%	1520
December	1st to 10th	Day	28% 14% 4 8% 4 4 4 3 4 5% 23%	1520
	11th to 20th	Day	29% 14% 4 10% 7% 4 4 3 3 5% 16%	1879
	21st to end	Day	24% 16% 6% 10% 5% 5% 5% 4 4 5% 14%	2442
January	1st to 10th	Night	33% 16% 4 9% 6% 4 4 3 4 3 13%	4726
	11th to 20th	Night	27% 13% 3 7% 4 3 4 3 4 9% 23%	4466
	21st to end	Night	33% 15% 4 10% 5% 5% 4 4 4 5% 12%	4818
February	1st to 10th	Night	31% 13% 3 7% 5% 4 4 3 4 5% 20%	2470
	11th to 20th	Night	26% 15% 3 9% 5% 4 4 3 4 5% 22%	2402
	21st to end	Night	27% 14% 3 8% 5% 4 5% 4 5% 5% 20%	1984
March	1st to 10th	Night	21% 14% 4 11% 7% 6% 6% 4 6% 5% 17%	3658
	11th to 20th	Night	21% 11% 3 5% 3 3 3 3 5% 6% 37%	3489
	21st to end	Night	28% 14% 4 9% 6% 4 5% 3 5% 4 17%	3689
April	1st to 10th	Night	25% 11% 3 10% 5% 4 5% 5% 6% 7% 19%	1900
	11th to 20th	Night	22% 10% 3 9% 5% 6% 5% 4 5% 5% 27%	1842
	21st to end	Night	25% 11% 3 9% 7% 5% 4 3 5% 5% 23%	1653
May	1st to 10th	Night	18% 8% 2 6% 4 3 3 3 4 4 44%	2540
	11th to 20th	Night	15% 7% 3 6% 5% 5% 3 3 5% 6% 43%	2516
	21st to end	Night	28% 9% 3 7% 5% 4 4 3 4 6% 26%	2762
June	1st to 10th	Night	20% 10% 2 6% 6% 4 5% 3 5% 7% 31%	1419
	11th to 20th	Night	23% 10% 4 8% 5% 4 5% 4 5% 5% 27%	1330
	21st to end	Night	14% 7% 2 6% 4 4 3 5% 6% 7% 42%	1330
July	1st to 10th	Night	8% 4 2 4 3 2 2 2 3 4 67%	2220
	11th to 20th	Night	5% 3 1 3 2 2 2 2 3 5% 73%	2343
	21st to end	Night	12% 4 1 4 3 3 3 3 5% 5% 57%	2762
August	1st to 10th	Night	5% 2 1 2 2 2 3 3 4 7% 69%	2574
	11th to 20th	Night	14% 6% 2 6% 3 3 3 3 4 6% 51%	2812
	21st to end	Night	17% 6% 2 6% 3 3 3 3 4 5% 48%	3328
September	1st to 10th	Night	9% 4 2 5% 3 4 4 3 5% 6% 55%	1900
	11th to 20th	Night	16% 8% 3 7% 4 4 4 3 4 5% 40%	1900
	21st to end	Night	17% 7% 3 8% 4 4 3 4 4 6% 41%	2167
October	1st to 10th	Night	17% 9% 3 8% 5% 5% 4 3 5% 6% 36%	2280
	11th to 20th	Night	26% 8% 3 6% 4 4 4 3 5% 6% 32%	2280
	21st to end	Night	27% 10% 3 8% 4 3 4 3 5% 6% 27%	2633
November	1st to 10th	Night	33% 11% 3 7% 5% 4 4 3 4 5% 20%	2568
	11th to 20th	Night	32% 13% 3 7% 4 3 4 4 4 5% 21%	2660
	21st to end	Night	33% 12% 3 7% 5% 4 4 3 4 5% 20%	2660
December	1st to 10th	Night	28% 13% 3 6% 5% 3 3 3 5% 5% 25%	2660
	11th to 20th	Night	29% 14% 5% 9% 6% 4 5% 3 4 5% 16%	3321
	21st to end	Night	27% 16% 5% 11% 6% 5% 4 4 4 5% 13%	5214

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	76% 10% 6% 6% 2	2219
	11th to 20th	Day	59% 10% 13% 14% 4 1	2451
	21st to end	Day	78% 7% 7% 6% 1	2835
February	1st to 10th	Day	69% 10% 10% 7% 3 1	1710
	11th to 20th	Day	66% 10% 9% 8% 7%	1674
	21st to end	Day	65% 10% 10% 10% 5%	1470
March	1st to 10th	Day	56% 14% 15% 11% 4	3200
	11th to 20th	Day	49% 11% 15% 23% 2	3490
	21st to end	Day	64% 14% 13% 9% 1	3963
April	1st to 10th	Day	63% 14% 14% 9% 1	2280
	11th to 20th	Day	59% 10% 12% 12% 6% 1	2286
	21st to end	Day	60% 12% 12% 11% 5%	2527
May	1st to 10th	Day	44% 11% 13% 22% 10%	4420
	11th to 20th	Day	38% 15% 24% 19% 4	4380
	21st to end	Day	61% 12% 17% 9% 1	4814
June	1st to 10th	Day	52% 11% 18% 13% 6% 1	2758
	11th to 20th	Day	56% 12% 16% 12% 3	2850
	21st to end	Day	41% 12% 19% 20% 7% 1	2850
July	1st to 10th	Day	22% 7% 11% 23% 24% 13%	4666
	11th to 20th	Day	19% 6% 10% 31% 31% 4	4532
	21st to end	Day	29% 6% 19% 31% 14% 2	4639
August	1st to 10th	Day	20% 8% 16% 37% 19% 1	4337
	11th to 20th	Day	38% 9% 21% 24% 6% 2	4065
	21st to end	Day	42% 8% 12% 26% 11% 1	4344
September	1st to 10th	Day	35% 8% 16% 24% 13% 4	2280
	11th to 20th	Day	44% 10% 14% 17% 15% 1	2280
	21st to end	Day	45% 10% 18% 17% 8% 2	2008
October	1st to 10th	Day	49% 12% 15% 18% 6%	1900
	11th to 20th	Day	58% 8% 15% 14% 5% 1	1900
	21st to end	Day	64% 7% 11% 11% 7%	1964
November	1st to 10th	Day	67% 9% 12% 7% 4	1516
	11th to 20th	Day	65% 10% 9% 9% 6% 2	1520
	21st to end	Day	67% 7% 8% 11% 7% 1	1520
December	1st to 10th	Day	65% 6% 10% 10% 8% 1	1520
	11th to 20th	Day	69% 11% 10% 8% 2 1	1882
	21st to end	Day	70% 11% 11% 5% 2	2442
January	1st to 10th	Night	74% 11% 6% 6% 2 1	4726
	11th to 20th	Night	58% 8% 12% 17% 4 1	4504
	21st to end	Night	74% 9% 8% 7% 2	4818
February	1st to 10th	Night	68% 7% 10% 9% 4 1	2470
	11th to 20th	Night	64% 9% 10% 10% 6% 1	2404
	21st to end	Night	63% 9% 11% 12% 4 1	1984
March	1st to 10th	Night	61% 13% 11% 10% 4	3658
	11th to 20th	Night	46% 10% 18% 23% 2 1	3490
	21st to end	Night	68% 11% 13% 8% 1	3689
April	1st to 10th	Night	61% 13% 14% 10% 2	1900
	11th to 20th	Night	57% 10% 13% 12% 7% 2	1842
	21st to end	Night	60% 11% 12% 11% 6% 1	1653
May	1st to 10th	Night	41% 11% 14% 26% 8% 1	2540
	11th to 20th	Night	37% 14% 24% 20% 5%	2516
	21st to end	Night	60% 14% 16% 10% 1	2762
June	1st to 10th	Night	53% 8% 19% 14% 5% 1	1419
	11th to 20th	Night	57% 11% 17% 13% 2	1330
	21st to end	Night	40% 9% 23% 19% 5% 3	1330
July	1st to 10th	Night	23% 5% 10% 25% 21% 15%	2185
	11th to 20th	Night	16% 5% 10% 28% 39% 2	2301
	21st to end	Night	30% 7% 13% 29% 18% 3	2674
August	1st to 10th	Night	17% 5% 15% 41% 19% 2	2566
	11th to 20th	Night	35% 7% 23% 24% 9% 2	2839
	21st to end	Night	40% 7% 16% 27% 10%	3328
September	1st to 10th	Night	30% 8% 17% 27% 13% 4	1900
	11th to 20th	Night	46% 7% 11% 18% 14% 3	1900
	21st to end	Night	45% 8% 14% 22% 9% 1	2167
October	1st to 10th	Night	47% 9% 14% 22% 7%	2280
	11th to 20th	Night	52% 9% 16% 16% 6%	2280
	21st to end	Night	57% 9% 12% 15% 7%	2633
November	1st to 10th	Night	67% 8% 11% 11% 3 1	2568
	11th to 20th	Night	65% 8% 10% 10% 5% 2	2660
	21st to end	Night	65% 9% 9% 10% 7% 1	2660
December	1st to 10th	Night	61% 8% 11% 13% 6%	2660
	11th to 20th	Night	69% 11% 11% 5% 3 1	3317
	21st to end	Night	70% 13% 9% 6% 2	5214

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	38% 10% 16% 15% 12% 9%	180
	11th to 20th	Day	35% 16% 12% 15% 16% 7%	180
	21st to end	Day	44% 9% 15% 15% 13% 4	226
February	1st to 10th	Day	41% 12% 16% 18% 10% 2	370
	11th to 20th	Day	39% 10% 18% 21% 10% 2	365
	21st to end	Day	35% 14% 18% 22% 9% 1	334
March	1st to 10th	Day	31% 16% 22% 18% 11% 2	460
	11th to 20th	Day	32% 13% 13% 21% 15% 6%	460
	21st to end	Day	33% 13% 23% 20% 10% 1	506
April	1st to 10th	Day	32% 13% 20% 20% 11% 3	460
	11th to 20th	Day	23% 16% 26% 20% 10% 6%	452
	21st to end	Day	26% 15% 20% 24% 13% 3	460
May	1st to 10th	Day	18% 11% 23% 30% 14% 3	463
	11th to 20th	Day	22% 8% 19% 25% 19% 6%	488
	21st to end	Day	24% 11% 19% 24% 16% 7%	529
June	1st to 10th	Day	21% 10% 23% 28% 15% 3	588
	11th to 20th	Day	21% 10% 27% 25% 14% 3	680
	21st to end	Day	12% 7% 24% 31% 21% 5%	680
July	1st to 10th	Day	12% 5% 20% 35% 25% 4	671
	11th to 20th	Day	8% 6% 18% 36% 25% 7%	593
	21st to end	Day	9% 3 15% 36% 27% 10%	531
August	1st to 10th	Day	12% 3 11% 36% 27% 11%	487
	11th to 20th	Day	7% 4 14% 34% 28% 13%	477
	21st to end	Day	14% 6% 21% 30% 21% 9%	539
September	1st to 10th	Day	15% 7% 19% 35% 19% 6%	490
	11th to 20th	Day	16% 9% 19% 30% 22% 5%	490
	21st to end	Day	22% 10% 20% 26% 17% 6%	490
October	1st to 10th	Day	24% 9% 18% 24% 18% 7%	490
	11th to 20th	Day	31% 10% 17% 20% 16% 6%	490
	21st to end	Day	34% 11% 17% 20% 13% 5%	413
November	1st to 10th	Day	41% 11% 19% 17% 9% 3	194
	11th to 20th	Day	37% 12% 11% 15% 13% 12%	180
	21st to end	Day	38% 9% 18% 13% 10% 12%	180
December	1st to 10th	Day	44% 12% 9% 9% 13% 13%	180
	11th to 20th	Day	46% 12% 12% 17% 11% 2	180
	21st to end	Day	43% 8% 14% 24% 9% 2	198
January	1st to 10th	Night	45% 12% 10% 18% 13% 2	850
	11th to 20th	Night	40% 11% 10% 19% 18% 3	781
	21st to end	Night	38% 8% 14% 22% 15% 3	836
February	1st to 10th	Night	39% 8% 12% 26% 12% 3	760
	11th to 20th	Night	34% 10% 12% 24% 17% 2	744
	21st to end	Night	36% 9% 13% 25% 14% 3	628
March	1st to 10th	Night	34% 13% 14% 21% 16% 2	760
	11th to 20th	Night	35% 12% 13% 22% 14% 3	760
	21st to end	Night	35% 13% 17% 22% 11% 1	836
April	1st to 10th	Night	31% 12% 14% 25% 16% 3	760
	11th to 20th	Night	27% 11% 18% 25% 16% 4	714
	21st to end	Night	31% 9% 16% 29% 13% 3	513
May	1st to 10th	Night	19% 9% 14% 33% 23% 3	380
	11th to 20th	Night	21% 4 14% 26% 30% 4	374
	21st to end	Night	25% 6% 12% 26% 26% 6%	411
June	1st to 10th	Night	25% 5% 15% 29% 23% 3	380
	11th to 20th	Night	26% 7% 13% 34% 18% 2	380
	21st to end	Night	17% 3 13% 36% 26% 5%	380
July	1st to 10th	Night	12% 4 9% 35% 36% 4	370
	11th to 20th	Night	8% 4 11% 36% 36% 5%	368
	21st to end	Night	9% 2 8% 33% 41% 7%	416
August	1st to 10th	Night	12% 1 6% 26% 43% 13%	397
	11th to 20th	Night	10% 2 5% 23% 45% 15%	564
	21st to end	Night	14% 4 9% 29% 36% 8%	731
September	1st to 10th	Night	13% 3 9% 34% 32% 9%	760
	11th to 20th	Night	20% 6% 10% 21% 32% 10%	760
	21st to end	Night	24% 7% 11% 27% 25% 7%	760
October	1st to 10th	Night	22% 6% 11% 28% 26% 8%	760
	11th to 20th	Night	31% 8% 13% 22% 21% 6%	760
	21st to end	Night	33% 10% 14% 25% 14% 4	836
November	1st to 10th	Night	39% 11% 14% 24% 11% 1	742
	11th to 20th	Night	39% 11% 15% 18% 14% 3	760
	21st to end	Night	40% 8% 13% 19% 14% 5%	760
December	1st to 10th	Night	36% 8% 12% 23% 17% 5%	760
	11th to 20th	Night	43% 11% 12% 20% 12% 1	773
	21st to end	Night	43% 12% 16% 19% 10% 1	935

Page generated at 2024-10-29 08:20:47. Version ac07

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